1. Field of the Invention
The invention relates to a light emitting device, more particularly to a light emitting device applicable to a backlight module, a displayer, a luminescent device, and the like.
2. Description of the Related Art
A first type of a conventional LED assembly for emitting white light includes a first LED emitting red light, a second LED emitting green light, and a third LED emitting blue light. The LED assembly can emit white light by combining the red, green, and blue lights, and adjusting the ratio of the light intensities of the first, second, and third LEDs.
A second type of a conventional LED assembly for emitting white light includes a LED emitting blue light and a fluorescent material excitable by the blue light to emit a substantially yellow light. The substantially yellow light emitted by the fluorescent material is combined with the blue light from the LED to produce white light. For example, U.S. Pat. No. 5,998,925 discloses such a LED assembly.
However, in the first type of the conventional LED assembly, since three LEDs are required for each LED assembly, the size of each LED assembly is relatively large, and the production cost thereof is relatively high as well. As for the second type of the conventional LED assembly, since the intensities of the red and green light portions are insufficient, the color rendering index (CRI) of the second type of the conventional LED assembly is inferior. Furthermore, when the second type of the conventional LED assembly is used as a light source for a liquid crystal display, most of the yellow light portion cannot pass through a color filter, which merely permits red, blue, and green light to pass therethrough. Therefore, illumination intensity of the liquid crystal display is insufficient.